This invention is directed to a medical sampling device for use with gynecological examinations, particularly to an improved method of obtaining endocervical cell and tissue samples during colposcopy.
The most widely used cervical cancer screening test is the well-known pap smear. When an abnormality is detected, further evaluation and follow up are warranted. The most common follow up test after an abnormal pap smear is colposcopy. Colposcopy is a visual inspection of the lower genital tract using a low power microscope. This test is limited to visualization of the surface of the uterine cervix, and cannot adequately detect problems within the endocervical canal. The incidence of cervical adenocarcinoma is increasing. It is estimated that up to 20% of cervical cancers occur within the cervical canal, and are not readily visible during colposcopy. Because of this significant limitation of colposcopy, the cells and tissues of the endocervical canal must be adequately sampled to allow for microscopic evaluation and accurate diagnosis. Appropriate endocervical sampling can present further diagnostic excisional (surgical) procedures in the majority of patients.
There are presently several commonly used methods to sample the endocervical canal. It is estimated that the total annual cost of aggresive management is almost four billion dollars in the United States alone. One method to sample the endocervical canal is the endocervical curettage. This method employs utilizing a xe2x80x9ccurette,xe2x80x9d generally a metal instrument with sharp edges which scrape the walls of the endocervical canal.
A disadvantage of the curette method is that this method generally suffers from a poor cell yield. This leads to inadequate sampling and xe2x80x9cfalse negativexe2x80x9d results, thus requiring further investigation. This includes repeat sampling or surgical intervention, such as cone biopsy or other excisional procedure. This potentially causes an increase in patient discomfort, morbidity and cost.
A second disadvantage is that upon insertion of the curette into the cervical os (opening), the curette often inadvertently scrapes or xe2x80x9cnicksxe2x80x9d the ectocervix, (surface of the cervix) causing a xe2x80x9cfalse positivexe2x80x9d result, necessitating further evaluation. This, again, potentially causes increased discomfort, morbidity and cost.
Another disadvantage of the curette method is patient discomfort as the specimen xe2x80x9cscrapesxe2x80x9d along the endocervical walls.
Another disadvantage of the curette method is cost to process the specimen. In most institutions, the specimen obtained in this manner is processed xe2x80x9chistologically,xe2x80x9d that is, by the pathology department. In general, this cost is greater than with samples obtained with brush methods.
Another disadvantage of the curette method is the need to sterilize the instrument, increasing the potential of infection to the patient and health care workers, and adding to increased overall cost of care.
Another common method of evaluating the endocervical canal is with a standard cytology brush. While this method improves cell yield over the curette, it suffers from ease of contamination of the brush from cells or tissues at or near the canal opening, as the brush is inserted and withdrawn, causing xe2x80x9cfalse positives.xe2x80x9d This xe2x80x9cfalse positivexe2x80x9d rate remains a major weakness of the brush method and potentially leads to further evaluation. This increases patient discomfort, morbidity and cost.
Another disadvantage of the standard cytology brush evaluation of the endocervical canal is lack of sterility of most commonly used cytology brushes. These are generally purchased in bulk and cannot be sterilized just prior to use during colposcopy.
Another method to sample the endocervical canal during colposcopy utilizes a cytology brush with a standard drinking straw as a protective sheath. There are several key disadvantages to this system. The first disadvantage is that the opening of a standard drinking straw does not accommodate the majority of cervical opening sizes. This is secondary to its fixed opening size, and the lack of conformity to the cervical opening. In addition, the straw is awkward to handle and manipulate, often slipping from the operators gloved fingers.
Another disadvantage is the need, in most cases, to cut and trim the straw to a length less than the cytology brush, adding extra steps to the procedure and decreasing efficiency.
Another disadvantage is that the brush often inadvertently advances forward before the operator is ready to sample, potentially causing the specimen to become contaminated with cells or tissues from the ectocervix.
Another disadvantage is the inability of the operator to determine the depth of insertion into the endocervical canal.
Another disadvantage is the inability of the operator to judge the position of the brush back in the protective sleeve prior to withdrawal.
Another disadvantage is the straw edges are sharp having the potential to cause tissue trauma or crushing artifact of the specimen.
Another endocervical brush assembly and method is disposed in U.S. Pat. No. 5,456,265 by Yim issued 10/10/95. This device suffers from several of the same shortcomings as the brush-plus-straw method. First, the opening size of the distal tip will not accommodate the majority of cervical openings. A second disadvantage is that the distal end is covered by a small cap which must be removed prior to insertion. Failure to remove this cap could potentially result in a foreign body being left in the patient. A third disadvantage is that it is difficult for the operator to determine the depth of insertion into the endocervical canal. A fourth disadvantage is that after the cap is removed, the distal brush bristles remained unprotected as insertion proceeds, risking contamination to the endocervical specimen with cells from the ectocervix. A fifth disadvantage is that this device requires bimanual operation.
With the high number of abnormal pap smears, and the high incidence of error associated with curette sampling methods, there is a need for an inexpensive, accurate, simple, safe, and effective method to collect endocervical cells.
In accordance with the present invention, an endocervical sampling device comprising a cytology brush encased in a protective sleeve, and a tapered distal tip with a protective penetrable seal.
It is a general object of the present invention to provide an endocervical sampling device which solves the technical problems long associated with endocervical sampling while overcoming the disadvantages of the prior art. Several objectives and advantages of the present invention are:
(a) To provide an inexpensive endocervical sampling device which protects the integrity of the sample by protecting the brush from contamination from tissue and cell fragments on the endocervix during insertion or withdrawal.
(b) To provide an inexpensive endocervical sampling device that accommodates the majority of cervical opening sizes, eliminating the need for multiple devices.
(c) To provide an inexpensive endocervical sampling device that provides the operator with visual confirmation of the position and depth of the brush within the endocervical canal.
(d) To provide an inexpensive endocervical sampling device for sterile, single use application to minimize the risk of infection to the patient and health care workers.
(e) To provide an inexpensive endocervical sampling device that promotes patient comfort.
(f) To provide an inexpensive endocervical sampling device that is easy to maneuver.
(g) To provide an inexpensive endocervical sampling device that minimizes tissue trauma.
(h) To provide an inexpensive endocervical sampling device that prevents inadvertent forward advancement of the brush minimizing premature contact with the brush and the canal, thus, decreasing xe2x80x9cfalse positivexe2x80x9d samples.
(i) To provide an inexpensive endocervical sampling device with a tapered distal end which protects the integrity of the brush bristles while resting in the sleeve.
(j) To provide an inexpensive endocervical sampling device that can potentially improve sensitivity of endocervical cell sampling, leading to a more accurate diagnosis of endocervical cancer or pre-cancer.
(k) To provide an inexpensive endocervical sampling device that is disposable.
(l) To provide an inexpensive endocervical sampling device that is efficient, requiring minimal steps to operate.
Briefly described and in accordance with one embodiment, the invention provides an endocervical sampling device and method for efficiently and inexpensively collecting samples of endocervical cells and/or tissue from the walls of the patient""s endocervical canal.
Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.